Train control system for railroads



Sept. 13, 1932;

C. S. BUSHNELL TRAIN CONTROL SYSTEM FOR RAILROADS Filed Aug. 7, 1930 Fatented Sept. 13, 1932 UNITED STATES PATENT oFF cE SIGNAL COMPANY, OF ROCHESTER, NEW YORK TRAIN CONTROL SYSTEM: FOR RAILROAIDS App lication filed August 7, 1930. s m 1%. 473,522. r

This invention relates to train control systems, and more particularly to acknowledging apparatus for such systems.

In the application of automatic train control to railway systems, andparticularly automatic train control of permissive type, ti has been found expedient to require the engr.

neer to operate suitable acknowledging means to manifest his vigilance and his recognition of the passage of his train by a signal at caution. or stop. This. acknowledging apparatus is usually a device'for preventing a re striction in the progress of the train if manually'operated at the proper time. In order to prevent the engineer misusing this apparatus, as by tying it down,it has been found expedient to limit the time during which this acknowledging device. may assume its active position by imposing a penalty if it is maintained active too long. This penalty in some cases resided in bringing the train to a stop in the event the device were held 1n 1ts active position longer than a predetermined period of time. Acknowledging apparatus protect- "ed only inthis way is not entirely safe, be-

cause -it wouldbe possible for the engineer to hold his actin device in its'active condition substantially continuously, in that if he intermittently allowed it to assume its inactive position momentarily at time intervals less than said first mentioned interval of time'the engineer could perform the-ac knowledging act without observing the condition of the waysidesignal. In order to ford better protection against misuse of the acting device, it is proposed in accordance with the present invention topermit functioningof the apparatus onlyat intervals of time greater than said first mentioned interval of time. I

Other objects, purposes and characteristic features of the present invention will inpart be obvious from the accompanying drawing -and will in part be more specifically pointed out hereinafter. v r i In describing the invention in detail reference will be made to; the single drawing showing conventlonally the car carried and trackway apparatus of a train control sys- 'temof the intermittent inductive type,to

. be operated to avoid a brake application.

present invention has been shown system disclosed therein is generally of the type as shown in my prior Patent no. 1,686,434; dated October 2, 1928, upon which system has been superimposed the improved l acknowledging apparatus of the present invention. The car carried apparatus includes the normally energized electro-pneumatic valve EPV, which if de-energized applies the brakes or restricts the train in vany other suitable way, the primary relay R the secondary relay R and the main relay R which relays are controlled through the medium of the secondary coil S of the car carried receiver IR, through the medium of flux emittedby the primary'coil P. This car carried apparatus also includes the acknowledging relay A, the acknowledging device Aclr:

: including time element devices T andT and the whistle valve WV.

The trackway apparatus includes a wayside signal'WS controlled in accordance with traffic conditions in advance in the usual manner, a line relay LR similarly controlled, and an 7 inductor TE which is'normally held inactive by having its winding W short circuited through a front contact 1 of the line relay LR, and which inductor if active will induce a voltage impulse in the secondary coil S of thecar carried receiver IR upon passage of suchreceiver over said inductor. Having I now briefly described the various elements of I the car carried and trackway apparatus, it

is believed expedient to discuss the normal I condition ofthe apparatusandthe manner in which the acknowledging device A070 must I Operation The train control device EPV is, normally energized through the following circuit beginning at the terminal front contact 2 of the relay R wires 3, i, and 5, front contact 6 of the relay R wires 7, 8, and 9..

contact 10 of the reset push buttonRes, wire 11, normally closed timingcontact Z of the acknowledging contactor Ack, wire 12, winding of the device EPV, to the other terminal CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASSIGNOR 'IO GENERAL RAILWAY: 71 f of a suitable source of current on the train.

Similarly, the main relay R and the primary coil P of the car carried inductor IR 5 are normally connected in series through the following energizing circuit :-beginning at the terminal (-1-), front contact 2 of the secondary relay R wires 3, 4t and 5, front stick contact 6 of the relay R wires '7 and 10 13, winding of the relay R wiresil't and 15, primary coil P to the other term-inall of the same battery. Attention is directed to the fact that-the main relay R not only serves to control the flow of current to the electro pneumatic valve 'E'PV, but also serves tionate to the current flowing through the primary coil P, :this being an important-feature *of the .car carried apparatus as more 'fully described in my prior patent above mentioned. I

The primary relay R is connected in series with the secondary coil S of the inducti-vecar I element 13, and is energized by the drop of tpotentialacrossthe relay B through the following circuit :beginning at the left hand terminal 13 of the relay R wires .8 and 16., front stick contact 1.7 of the relay R wires 18 and19, secondary winding S of the rerceiver IR, wires .20 and 21, winding'of the primary relay R wire 22, bsack'to the other terminal 14 of the relay R The secondary relay R is normally energized through the following stick circuit beginning at theterminal of said car battery, front stick contact 2 of the relay R wires 3, 4, and 5, front contact 6 of the relay 12%, wires '7, 8, and 16, frontcontact 17 of the relay R wire 24, winding of the rela-y R to the other terminal I) of said car battery. The acknowledging relay A ;-is'

slightly slow actingas conventionally shown,

and is normally energized through the fol-- lowing circuit :beginnin at the terminal 1+) of said car battery, timing contact'25 of the timing device T wires 26 and 27, windingof the :relay A to the other terminal of said battery.

It may be pointed out here that the stop- 69 ping influence is transmitted :from the trackway to the car carried'app'aratus of the present system uponpassage of the car by the trackway inductor TE, the choke coil of In: which is open circuited, by 'the receiver IR being-quickly and momentarily bridged by It is of course understood that passage of the car elementlli oyerathe track element TE when the choke coil W of the track element is dlosed in a circuitof low resistance will have no efi'ect on the car carried apparatus.

Let us now assume that the railway car equipped with the car apparatus shown in the drawings .passes by the track inductor TE with its winding open circuited, and let us observe how the brakes are appliedon'the assumption that the engineer .has failed to operate the acknowledging device A070. Passage of the receiver 1R over the inductor TE under the conditions assumed, causes a counter electromotiye force to be induced in the circuit of the primary relay R thereby causing this primary relay R to be de-energized and in turn effecting de-energizationof the relay R Dropping of the relay R by :the opening of its contact-2 removes energy from the relay R and the primarycoil P and also cuts energy ofi of the 'train control device so that movement of the train willbe restricted in a manner dependent on the construction of the device EPV,.as by abrake application, which restriction can only be a removed by the operation of the reset device Res, onlyaccessible from the ground.

Let us now assume that the engineer after bringing the train to a stop, steps 'to the ground and operates the reset device Res.

- In so doing, the main relay R will be picked up through the following pickup circuit:- beginning at the terminal (-1-), contact 10 of the reset device Res, wires .9, 8 and 13, Winding of the relay R wires 14 and 15., primary coil P to the other terminal of said :car battery. .Since there is now a potential :drop over the relay 3?, and with the reset ,push button Res still depressed,

the primary relaylit is COIll'lBCtGCliflCIOSS the relay -R through thefollowing circuit beginning at the left hand terminal 13 of the relay R wire 8, contact 30 of the reset device Res, wires 31 and 21, winding'of the relay R .and wire .22, back .to the right hand terminal l' tof the relay R3. With the relay R once energizedits stickcircuitinclud- 'ing the secondary winding S, heretofore traced, is again closed. lVith the relay R again picked up and with the reset push button :Res still depressed the secondary relay R is picked up through the following circuit:-beginning at the terminal contact 10 0f the reset push button Res, wires 9 and 16, front contact 17 of the relay R wire 2%, winding of the secondary relay R With the relay R now energized and its contact 2 closed current may flow to the relays R R and R and to the primary coil P and also to the device EPV, so that the reset button Res may be released, and the car carried apparatus is restored to its normal condition.

Let us now assume that the train approaches the signal 7 at caution or stop and that the engineer is vigilant and operates his acknowledging handle A070 to the dotted position. Under the conditions of traflic assumed the relays R and R will be deeenergized in exactly the same manner as heretofore described, but the main relay R w1ll remain energized through the medium of the following auxiliary circuit including the acknowledging contact X :beginning at the terminal winding of the whistle valve WV, wire 32, acknowledging contact X, wire 33, front contact at of the acknowledging relay A, wires 35, 4 and 5 front contact 6 of the relay R wires 7 and 13, winding of the relay R wires 14 and 15, primary coil P to the other terminal to the car battery. So long as current flows through the circuit just traced the whistle valve WV will sound thereby informing the engineer that a stop influence has been transmitted from the trackway to the vehicle and that he has passed a signal at caution or danger.

Also, during this acknowledging period the device EPV is held energized through the following circuit :beginning at the terminal whistle valve WV, wire 32, acknowledging contact X, 33, 34, 35, 4, 5, 6, 7,8, 9,10, 11, contact Z, 12, winding of the EPV to the other terminal It may be pointed out here that operation of the acknowledging device A070 to its dotted position will effect closure of the contacts X and Y through the medium of the arm 37 having a pin 38 operating in the slot of thearm 39. Also, that movement of the acknowledging handle A070 to the dotted position will cause the piston 40 in the timing device T to be moved toward the right thereby opening the contact 25. Also, movement of the lever A070 to the dotted position closes the contact 41 included in a stick circuit of the acknowledging relay A containing the stick contact 42 or relay A, and the wires 43 and 4A. The relay A is sufficiently slow dropping so that movement of the acknokledging handle to itsnormal dotted position in the usual way will allow the contact 41 to be closed before the contact 25 opens, so that the acknowledging relay A will remain energized during the act of acknowledgment.

Not only does operation ofthe acknowledging contactor A070 to its dotted position complete circuits for maintaining the device R 5 and EPV energized but the following pick-up circuitfortherelay R is also completedr beginning at the terminal. winding. of the valve WV, wire 32, contact X, wire 33, contact 34 of relay A, wires 35, 4 and 5, front contact 6 of relay R wires 7 and 55, back 1 contact 56 of-relay R wire 57, front contact 58 of relay A, wire 59, acknowledging contact Y, wires 60 and 19, secondary coil S, wires 20 and 21, winding of the relay R to the junction between relay B so that the potential drop across relay R is applied tothe pick-upcircuit for relay R This will of course relay R will in turn pickup the relay R after which the acknowledging handle Ack contact Z;.will be opened by action of'the spring 50 moving the piston 40 into the cylinderof the timing device '1 to a point where the. contact Z is opened, automatic application of the brakes or the like, will occur. The specific time element devices T and T illust 'ated include adjust-I whereby the and the time able vent valves 1 and 51 time of opening th'econtact Z of reclosing of the contact-25 after operation and return to normal, respectively, of the acknowledging handle A070 may be accurately adjusted. In practice, the timing device T is preferably so adjusted that thecontact 25 will not reclos'e until a much larger interval of time has elapsed, than the time required for contact Z to open, such forinstance as 30 seconds, after the acknowledging handle A070 has been returned to its normal position.

Also,as will be noted from the drawing the pistons40 and 40 are pistons of thevalve type which may be freely drawn out but which are airtight for the return movement, so that they serve the double function of a valve and piston. From this it will appear that the acknowledging relay A will remain deenergized after each operationand return to normal of the acknowledging handle A070 for a period of 30 seconds, and since the con-' tact 34 of this relay Amust be closed in order to permit the acknowledging act to become effective, the acknowledging apparatus of the system under consideration is available for use' only once during each period of 30 sec-- onds of time. In other words, since the engineer can render the acknowledging apparatus effective only once during a '30 second interval time it behooves the engineer to carefullyobserve' the wayside signals and indicators 7 and primary coil 1? pick up relay R which so that an andaoperate the acknowledging device attthe time or just before the car. carriedelementilR passesover thetrack element TE, this because he is permitted to; move the acknowledging handle Ada only once for each'inductor, considering the speed that a train ordinarily moves and considering the I ordinary :length of the blocks employed. I .Although the time devices :T and T 'have '6 beenconventionally illustrated astimingdevices of the dash-pot typeit isto'be understood'that the invention is not limited-tothe employment of time element devices o'f -this construction, and that time element devices ofthethermal element and clock work type may be employed i.f*desired.

Having thus shown and described one particular species of acknowledging apparatus w embodying the present invention and having 2 shown-it applied to an intermittent type of system of automatic train control, it is desired to be understood'that acknowledging apparatus embodying the present invention m may also be applied to continuous inductive 2'5 type train control systemsfior instance of the type as shown intheprior patent to W. K. Howe, No. 1,598,554,.granted July 20, 1926, and that various changes modifications and additions may be'made to the acknowledging apparatus embodying the present'invention to adapt itto the particular'type 'of train control system'inconnection with which it is tobe used, allwithout departing from the spirit or scope of the present invention or the idea of means underlyingithe sameexcept as demanded by the scope of the following claims. a 7

What I claim as new is '1. In a train control'system, a brake control apparatus on a vehicle, trafiic controlled means-partlyon the vehicle and partlyon the track for .governing'said apparatus in accordance with tra'fiic conditions, and manual- 1y Operable means having a limited interval 5' of time of efiective operation for maintaining the apparatus inactive independently of its control "by saidtraific controlled means, said manually operable means being effective .only at intervalssp'aced apart a predetermined period of time'and then only when said brake control apparatus is in its normal inactive condition.

2. In combination, a railway vehicle, a norrmally energized electrically operated brake control device energized by a stick circuit including its own frontcontact, control means for momentarily breakingsaid stick-circuit under adverse traffic conditions ahead, and acknowledging means for closing an aux- 6 iliary circuit for said brake control device effective for a limited time only and rendered available for use only onceduringa greaterperiod of time. a Intestimony whereof I aiiiX my signature.

'65 CHARLES S. BUSHNELL. 

